Safira Digitizer is free software built to help digitizing image (chart, map, etc.) to become number / numeric to be used for further calculations. Safira Ditizer is built using C++ programming language (Mingw32-gcc) on top of wxWidgets-3.0.2 library and CodeBlocks 13.12 & wxFormBuilder 3.5 IDE.
It is very simple and easy to use. Just simply import an image, do calibration, create data package and pick some points... once you've see it, certainly you will love it.
Safira Digitizer has been tested on the following OS: Windows XP, 7, and 8.1, and also Linux Mint 17.1 (Cinnamon and KDE), OpenSuse 13.2. The latest update version 1.01 bring some bug fix especially for linux (GTK).